@Nicholas_Ho can you please run ls -l ~/.daml/bin/daml from your shell and tell us the output?
It should print the full path to the daml executable if the installation succeeded.
$ ls -l ~/.daml/bin/daml
lrwxrwxrwx 1 leos leos 22 Jul 28 17:39 /home/leos/.daml/bin/daml -> ../sdk/1.3.0/daml/daml*